Well, it seems to me, that something that is being overlooked in this
discussion, is that for, many of us, buried radials are not an option. In
my case, I have bedrock that comes pretty much right up to the surface on
much of my lot that's available for antennas, and I have a long concrete
driveway, that runs pretty much the full length of my lot to a detached
garage that's near my small tower. The point is, that many of us without
large amounts of funds or real estate, simply have to accept the reality of
our situation and, work with what we have, and try to "flower where we're
planted". In my case I've worked lots of pretty good DX on all continents
and in all the oceans with an inverted L about 75 feet tall and supported by
a tall tulip poplar and had two elevated resonant radials, diametrically
opposed just above the level of the fence line around my small urban lot
here in Raleigh, NC and never more than 500 -600 watts. Some examples on
160, are 3B8, JA, VK, ZL, VK6, ZS6, ZD9.S79, KL7.KH6 ( many) KH5, KH5K,
KH7K, KH2, T32 , FO0, LOTs of Europeans. quite a few Africans, Lots of
South America, of course. I should point out that from Raleigh, NC VK6 is
pretty close to being the antipode. - And I wasn't a SERIOUS 160m op. I was
mostly chasing DX on 40 m and working everything that was around on as many
bands as possible with my "killer" 5-band quad. Worked everything on the
DXCC country list on CW except for North Korea. But generally, on 160, if I
could HEAR 'em, I could work 'em! Biggest problem was hearing!! But the
addition of a couple of 40' X 10' KAZ terminated receiving loops helped a
LOT!! - a LOT more than another 0.5 DB of TX antenna gain would have
afforded. As I said, "if I could hear 'em, I could work 'em"! An additional
0.5 or 1.0 DB on TX wouldn't have made much difference! And I had fun!!
There's a lot to be said for listening a LOT - for catching the DX when they
come up and working 'em before the "packet-rats" show up! In other words,
try to be there "when and where the competition ain't"! And BTW 160 doesn't
"die" in our summer - when it's winter in the Southern hemisphere. There's a
lot available on Topband in summer. Just have to listen a lot! Especially in
our mornings before and after our sunrise before a lot of the QRN from the
T-storms picks up! A lt of VKs, ZLs etc. available then! FWIW! Good huntn'
73,
Charlie, K4OTV
-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Richard
Fry
Sent: Friday, January 24, 2014 7:26 PM
To: topband at contesting.com
Subject: Re: Topband: Anyone purchased the ARRL book on Short Antennas
for160???
Guy Olinger postulated for a while, then wrote:
>... Run the four elevated over the radial field. ...
You posted that you have NEC4, Mr Olinger. Why not do that yourself then,
rather than ask someone else to do it for you? Post your results and the
bases for them, as I have done for my NEC4 analysis.
Your credibility will improve if your accurate NEC model results show that
the radiation efficiency of a vertical monopole using four, elevated,
1/4-wave radials when installed concentric with even a perfect set of 120 x
1/4-wave buried radials is significantly better than if those buried radials
were not present (other parameters the same). Let us define significant as
differing by more than 0.5 dB.
>The buzz I hear on the grapevine about 4 elevated is that's the remedy
>for a radial field gone sour, of course leaving the old radials
>*retired in place*.
The grapevine buzz you report about this subject is not worth further
dissemination, as no defensible documentation is available to support its
accuracy.
In any case, monopoles using only several, elevated, 1/4-wave radials have
been used by AM broadcast stations where it was impossible/impractical to
install ANY buried radials -- and those systems performed nearly as well as
if they were driven against a set of 120 x 1/4-wave buried radials (as I
posted previously) -- and they met/exceeded the FCC's minimum "efficiency"
requirements for those AM broadcast antenna systems for that class of
service.
There is no scientific reason why that same result would not apply to ham
operators with monopoles on the 160-meter band using ONLY several, elevated,
1/4-wave radials.
Or possibly even to those hams using monopoles with only an "FCP."
R. Fry
_________________
Topband Reflector Archives - http://www.contesting.com/_topband